Disk drives of the type known as "Winchester" drives or hard drives are well known in the industry. These disk drives are typically used in computer systems as mass storage devices to store recorded data. These disk drives usually incorporate one or more rigid disks coated with a magnetizable medium, mounted for rotation at a constant high speed on the hub of a brushless DC spindle motor. Data is recorded to and read from a plurality of concentric, circular tracks on the disks by an array of read/write heads. These heads are incorporated in assemblies which interact with the air pulled along by the spinning disks to "fly" the heads in close proximity to the disk surface. The heads are typically moved radially from track to track on the disks by an actuator assembly. A typical actuator assembly includes an actuator motor, a guidance mechanism to control the path of motion of the heads and support mechanisms to attach the heads to the moving actuator and support the heads in correct relationship to the disks. One such actuator assembly includes an actuator arm for supporting the read/write heads and a pivot assembly for rotatably supporting the actuator arm. The pivot assembly allows the heads to be moved radially with respect to the disks. A typical pivot assembly includes a pivot shaft around which the actuator arm pivots and one or two bearings mounted between the pivot shaft and a housing supporting the actuator arm.
Advances in disk drive technology have revolved around reducing the size of disk drive components and the size of the overall disk drive. Smaller disk drives can allow for a reduction in the overall size of the computer system into which the disk drives are installed. With the reduction in the size of the disk drive, more space is available within the computer system for other components. In addition to the small disk drives, the disk drive industry has also made advances toward increasing the storage capacity of individual disk drive units. This increased capacity has been brought about by increases in the linear density and track density of the magnetic disks.
The reduction in size of the disk drive can compound certain problems often associated with various operational features of disk drives. One such problem involves vibrations or harmonic oscillations in the disk drive. All disk drives experience a level of vibration or harmonic oscillations from various moving parts or electronic switching from within the disk drive or from the computer system. The effect of vibrations and oscillations has become magnified as the size of the drive is reduced and data tracks are spaced closer together. As a result, the overall performance of the drive is negatively impacted. In response to this problem, a number of solutions have been investigated which employ the use of rubber-like materials or elastomers within the disk drive for vibration dampening. However, these solutions have been found to have limited success.
Accordingly, there is a continuing need for additional methods to reduce vibration levels in disk drives even further and there is a need for a disk drive assembly exhibiting improved vibration dampening characteristics.